Origin is more fundamental than a magical attribute. It's the direction or essence every living being carries from the moment of birth.
You could call it instinct—but that's not quite right. Instinct is bound to the body, while Origin remains unchanged through countless reincarnations and body changes.
Instinct belongs to the flesh.Origin is rooted in the soul.
Most living beings, humans included, will go their entire lives without ever becoming aware of their Origin. But once awakened, Origin draws upon the accumulation of countless lifetimes, granting incredible power.
That said, awakening one's Origin isn't necessarily a blessing. Even among magicians, it's considered a taboo and deeply dangerous concept. Decades of human reasoning are nothing compared to the weight of a soul's eternal direction. Those who awaken may lose themselves entirely, becoming monsters driven only by their Origin.
The Origin of the Sword encompasses the sword's heart, its intent, its principles—every concept tied to the blade.
From the moment Shirou Muramasa realized his Origin was the sword, it began to awaken, unstoppable. His magic now flowed with a sharpness that seemed to cut through his veins and circuits, like a blade moving within his own body.
It was not a pleasant sensation—at times, it felt as if that sharpness might pierce outward and manifest as an actual sword at any moment.
But great risk often carries great reward. If Muramasa Shirou could master his Origin, he could stand on equal footing with Heroic Spirits themselves.
And with Doraemon at his side, he could afford to experiment as much as he wanted.
"Shirou, do you want to go back to your original body?" Doraemon asked curiously.
"Not exactly," Shirou replied. "I mainly want to feel the difference between my childhood body and my adult one. It'll help me understand and master my current power."
Shirou wasn't entirely sure what his future power would look like—or exactly how to reach it—but this method felt right.
In his original world, with the help of Tohsaka Rin and his future self, Archer (Red A), he had quickly mastered the magical reality marble Unlimited Blade Works.
Now, with Doraemon's help, he was determined to match—or even surpass—that.
He planned to compare the differences between bodies of different ages, hoping to find clues to his future path. It would be like the time he'd absorbed Red A's experiences, rapidly inheriting a lifetime of skill.
He already knew the eight steps for projection magic from his future self—identifying a concept, imagining its framework, replicating materials, imitating production techniques, empathizing with its history, and reproducing the weight of years. This time, he would apply them in reverse, to himself.
"Like spiritual training?" Doraemon asked, clapping his hands. "In Japan, people sometimes do that by sitting under waterfalls. I've seen it in anime."
"That's right."
"You really work hard," Doraemon said warmly. "If you were just an ordinary person, Shirou, you'd be a model child."
Shirou was taken aback—Doraemon's tone was exactly like a doting grandmother.
Puffing out his chest, Doraemon declared, "Leave it to me! As a childcare robot from the 22nd century, I'll complete my mission!"
He rummaged in his pocket. "Let's see… something to help with your training… Got it!"
Out came the Time Wrap, followed by a small bottle of candy-like pellets.
"These are Efficiency Enhancement Pills," Doraemon explained. "A special future food that boosts training or work efficiency by over a hundred times—no side effects."
"Thanks, Doraemon."
Without ceremony, Doraemon used the Time Wrap to revert Shirou's body to its six-year-old self. The sudden weakness was startling—his physical fitness had dropped far below his adult form, and the sharp-edged magic in his body had vanished entirely.
The Time Wrap could rewind the body's age, but left the mind and memories untouched.
Shirou opened the bottle, popped one pill into his mouth, and let it dissolve. It tasted like fluffy marshmallow—sweet, but not cloying.
Within seconds, power surged through him. His body brimmed with energy, his mind grew crystal-clear, and memories from both lives became sharper than ever—even those from his first moments in this life.
He set himself a task: Find the differences between bodies of different ages. His thoughts raced like a supercomputer, drawing conclusions and processing results without pause.
For a normal person, this pill alone could make them the smartest human alive.
Seeing Shirou so focused, Doraemon wisely didn't interrupt. As he walked away, he glanced back with a soft smile. "Do your best, Shirou."
A parenting robot's duty was to guide its owner's growth and offer every possible support. Compared to the unruly masters he'd seen in the 22nd century, Shirou was exceptional.
Time passed unnoticed as Shirou immersed himself in high-efficiency magical training.
Meanwhile, Miyamoto Musashi, who had spent most of the day wandering and eating under the pretext of "patrolling," returned to the Matou residence, hands full of snacks and skewered dumplings she'd somehow gotten for free.
"As expected, meatballs and udon are the best. This world is amazing—you can eat whatever you want without paying."
She stopped suddenly. In the middle of the courtyard stood a small red-haired boy, radiating an unusual aura.
A child?
No—there was something far more striking. She recognized it instantly: the boy was in a state of enlightenment, his presence slowly shifting toward the realm of Emptiness.
To reach the pinnacle of swordsmanship—Emptiness—a swordsman must pour their entire soul into the blade, honing their skill to perfection and uniting all possibilities into one.
This was the state Musashi herself now occupied, aided by her Heavenly Eye: the power to condense infinite possibilities into a single outcome. The harder step, however, was taking that one… and turning it into zero.
Like a butterfly emerging from its cocoon, such enlightenment would transform a swordsman into a true Sword Saint.
When did Emptiness become so easy to reach? she thought.
Suppressing her urge to draw her blade, Musashi stayed still. She knew how rare such a state was—each time she'd touched it herself, her swordsmanship had leapt to new heights. Disturbing someone in this moment could only create an unshakable grudge.